Steam turbine



Patented May 20, 117930 Plvrelarl um. nnna, or HANOVER, eruaiauuvsrv V y 7 v Application nl ed December 29, 1927, Serial No. 243,396, and in Germany .Tuney 23,1326.

-My invention relates to improvements in steam turbines. y l

For the economical utilization of smallv steam volumesin steam turbines, and particularly 1n the hlgh-pressure stages, it is neces- -sary to use small admission diameters in order v that the height of the blades may not drop below a minimum value. To prevent, fur-v thermore that the'number of stages becomes excessive ylarge, it appears advantageous to use two rotors running in opposite directions.

Up to now success has only been attainedin developing suitable constructions of turbines of the oppositely revolvin rotor typev with radial admission stages.k this case the admission diameter rises from stage to stage so quickly, however, that unfavorable flow condltions develop when the turbine is operated with high-pressuresteam.

Axial flow turbines with rotors revolving in opposite directions have also been suggested,

- ponderating axialfadmission, which is l r central bore of the outer rotor,` but when but have never attained any importance, be`

cause the suggestions disclosed up to now did -not contain-suicient datato base a practical construction upon them. These pro ositions` are in any, c'aseutterly unsuitable or highpressure steam.' V l running in opposite directions and with preable for industrial application.4 l

' I attain this obj ect by tage over the" prior art turbinesof the-double,v

form of anelongated cyhnder,` one portion of ywhich serves as a shaft and the other freeended portion, of slightly `larger diameter,

` servingeas 4a carrier of theblades, the live Y steam ing admitted throughl acentral bor.- ing provided in the shaft fportion of at least one rotor. This construction has the advantelescoped'rotor type, thatthe joints between the stationary androtaryportion'oftheturbine may be made of very small diameter, generally not much larger than the shaft 'diameter' and further that thereaction stresses occur-n shaft diameter, thus permittingmaterial reduction'in' weight and simplerfconstruction.

ving the rotorsthe.

The aforementioned shape of the rotors is particularly adapted .for 'very high pressure and speed, as compared with the drum shaped large diameter turbines of this type heretofore employed in the art, whopse packingjoint diameter is many times larger than the shaft z diameter, and Itherefore very unsuited for y high pressures and speeds'.

Iii-the drawings aliixed hereto and forming part of my specification two embodiments ofso my inventionv are' illustrated by way of example, representing in Fig. 1; an axial section through one embodiment, and in Fig. 2, asimilar section/through another ,expa'ndin them, by rolling'or the like, into My invention conslsts in providin a construction of a steam or. gas turbine wit rotors M A`regulation may beobtained vby admitting the 80 steam -forl small outputs merelythrou'gh the higher outputs are to be obtained through the bore of the inner rotor as well, the additional steam issuing between the blades at 85 .a row of blades which has a larger passage area than thev first row of blades.

For this purpose the central bore `of the inner rotor isclosed at the inner ,end of the. rotor 'and putin communication with *one of the" central .rows of blades by means of radial l i l bores. These central rows or stages present larger passage areas thanthe preceding' rows of smaller"-\diameter, in particular larger pas-A sages vthan the innermost row of blades. The

central stage of blades of the inner rotor thus takes at equal pressure larger 'quantities of the driving medium than the first stage.'

The dime'nsioning of tlie sta es connected in -Se'ies'il 'fOf the stage locate between the normal and the additional steam admission, takes place for the economical load which, asa rule, lies below the normal load. The number of vthestages bypassed by the additional driving medium depends upon the degree offoverload capacity demanded and the .output required of the machine with -decreasingpressure of the driving medium.

Fig.y 2 illustrates such a modification of the regulation. The inner rotor is indicatedby the/ reference letter a, the outer by I). In ay c ntral bore of the latter is accommodated the team supplypipe o. The steam, supplied by this pipe traverses all the rows of blades l 1 and thus also the stages d-d. The inner p rotor aA is likewise provided with a cent-ral bore, which however is closed at its inner end bythe plug l. The radial bores vf put the innerbore in the rotor a in communication with the rows of blades g to g. For small outputs the steam is admitted through the pipe c only. If the load has risen so high that full stream pressure exists in front of .the stage d, the steam pressure in front of the stage g will be lower on account of lthe drop of pressure in the `stages d to d. Al further increase of the output now takes place by the Vadmission of .additional steam 'through the pipe L in the bore -of the inner rotor a. This steam bypasses the stages d to l and. enters directly into the stage g and thus increases the pressure at this point. The pressure drop in the stages .d to d is thus reduced, and the quantity of steam flowing through the remaining stages and consequently the output of the turbine increased.

Various modifications and changes may be made without departing from the spirit and the scope of the invention, and I desire, therefore, that only such limit-ations shall be placed thereon vas are imposed by the prior art.

' v I claim as my invention: l

1. -In a steam turbine, in combination, an inner rotor, having a plurality of axially spaced peripheral rows of blades upon its outer circumference, an outer hollow rotor, carrying on its inner circumference axially spaced rows of inwardly directed blades, said outer rotor enveloping the inner rotor along its bladed portion, a lshaft for each rotor, carrying its rotor freely at its end, at least'one Uof said shafts having a central longitudinal vboring servin for admittinglive operating steam throng its interior to said rotors, an a .separate tubular 'steam conduit` disposed i within said shaft boring and being sealed at its ends atnarrow mar inal portions against the end portions of sai shaft boring.'

. 00 2. In a steam turbine, in combination,

. inner rotor, having a plurality of axially spaced .peripheral rows of;blades upon its outer'circumferenca an outer hollow' rotor, carrymg on its inner circumference axially e spaced rows of inwardly directedblades, said operating outer rotor enveloping the inner rotor along its bladed portion, a shaft for each rotor, carrying its rotor freely at lits end, each shaft having a central .longitudinal boring and a tubular steam conduit disposed in each shaft -boring and sealed at its ends against said shaft boring for .supplying live steam to said/ rotors. l. 1

3. Ijn a steam turbine, in combination, ran inner rotor, having a plurality of axially spaced peripheral rows of blades upon its outer circumference, an outer hollow rotor, carrying'on its inner circumference axially 'spaced rows of inwardly directed-blades, said outer rotor enveloping the inner rotor along its bladed portion, a shaft for each rotor, carrying its rotor freely at its end, ,each shaft having a central longitudinal boring and a tubular steam conduit disposed in each shaft boring and'sealed at its ends againstsaid shaft boring, said inner rotor having radial borings intermediate its ends for conducting live steam directly from said conduit between intermediate rows of blades representing i'ntermediate expansion stages of that rotor.

4. In a steam turbine, in combination, an inner rotor, having a plurality of axiallyv spacedv peripheral rows of bladesupon its outer circumference, an outer hollow rotor, v:carrying on itspinner circumference axially spaced rows of inwardly directed blades, said outer rotor -enveloping .the inner rotor along its bladed portion, a shaft for each rotor; carlrying its rotor freely at Aits-end, each shaft having' a central longitudinal boring and a tubular steam conduit disposed in-each shaft v boring and sealed at its ends a ainst said shaft boring,4 the steam conduit o said inner rotor being closed at its inner end, saidy rotor having radial borings leading from said conduit to intermediate rows of blades representling intermediatel expansion .stages of said rotor for conducting live steam directly to said stages.

5. In a steam turbine in combination anl elongated roller-shaped rotor, one of the rotorl portions serving as a shaft, the other, free ended portion beiner of slightly larger diameter and' having a plurality of .axia .peripheral rows of blades upon its outer circum'ference, a second rotor of similar configuration, one of its portions serving as a shaft and the other, free ended portion being of slightly larger diameter and surrounding the bladed portion of the first rotol` and having axially spaced peripheral rows of bladesl upon its outer and inner periphery, the shaft vv'portion of at least one rotor having a central longitudinal borin servin for admitting liveV steam t rough lts interior to said rotors. y' Y,

6. In a steam turbine in combination" an elongated roller-shaped rotor, one of the rotor portions serving'as'a-shaft, the other,

free ended portion being of slightly larger ly spaced' diameter and having a pluralit of axially spaced.4 peripheral rows of bla es upon its outer circumference, a second rotor of similar conguration, one of its portions serving as a shaft and the other, free ended portion being of slightly largerdiameter and surround- 4ving the bladed portion of the first rotor and having axially spaced peripheral rows of blades upon its outer and inner periphery,

the shaft portion of atleast one rotor having a central longitudinal boring serving for admitting live operating steam-through its interior to said rotors, and a. stator surrounding the b'laded portion of the second -rOtor 15" and'having a plurality of 'axially spaced peripheral rows of blades on its inner periphery to cooperate with the outer peripheral blades of said second rotor.V l

In testimony whereof I affix my signature.

2o KARL RDER.- 

